An increasing interest in organic Rankine cycle (ORC) technology has led to numerous simulation and
optimization studies. In the open-literature different modeling approaches can be found, but general software
tools available to the academic/industrial community are limited. A generalized ORC simulation
tool, named ORCSim, is proposed in this paper. The framework is developed using object-oriented programming
that easily allows improvements and future extensions. Currently two cycle configurations are
implemented, i.e. a basic ORC and an ORC with liquid-flooded expansion. The software architecture,
the thermo-physical property wrappers, the component library and the solution algorithm are discussed
with particular emphasis on the ORC with liquid-flooded expansion. A thorough validation both at component
and cycle levels is proposed by considering the aforementioned cycle architectures
